Fort Worth hospital giving its rooms an ultraviolet scrubdown

It can take 15 to 45 minutes to give a hospital room what's called a "terminal" cleaning, depending on the room's size and the contamination risks of the patient who occupied it.

The scrubdown is supposed to sanitize every surface, which according to a Centers for Disease Control checklist encompasses everything from bed rails and light switches to control panels and cables for the stacks of equipment used in a modern hospital.

But even then items can be missed, such as more than half the "high-touch" surfaces at three hospitals monitored by a Boston researcher in 2006.

Texas Health Harris Methodist Hospital Southwest Fort Worth recently rolled out a new weapon in the fight against hospital-acquired infections. It's one of about two dozen institutions in the country using a relatively new machine that uses ultraviolet light to kill bacteria and viruses.

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Xenex Healthcare's room disinfection device looks more like a trash can on wheels -- until its lid rises to reveal a faceted glass column. Inside is a powerful xenon bulb that emits intense 360-degree pulses of ultraviolet-C light.

Five minutes of exposure to UVC light, including reflected light, is enough to permanently damage a microorganism's DNA, company spokeswoman Melinda Hart said during a demonstration at the hospital. The victims include a bacterium of growing concern called Clostridium difficile, or C-diff, which infects the colon and spreads via a spore that can survive up to four months outside the body.

The cell-damaging properties of UV light have been known for more than a century. UVC is blocked by the earth's atmosphere (as well as ordinary glass). A longer UV wavelength, UVB, gets through and causes tanning and sunburns, and can cause skin cancer with excessive exposure -- also by damaging skin cells' DNA.

"We still do the manual cleaning -- that hasn't changed. But the UV light gets what we didn't get," said Kathy Rhodes, the hospital's coordinator of infection prevention. Right now the unit is being used in operating rooms.

The machine's cost, about $75,000, can be offset by avoiding just one serious infection, its maker says. According to the CDC, about 5 percent of U.S. patients hospitalized each year acquire an infection there. Just over 1 in 1,000 get a bloodstream infection related to the use of a large, long-term intravenous catheter, accounting for about a third of an estimated 99,000 deaths from hospital-acquired infections, according to various estimates.